The present inventions relate generally to improved shelf-type storage racks. More particularly, the present inventions relate to rack trusses that are bolted together for ease of shipment and assembly and/or which are reinforced at the bottom to prevent damage to the trusses by, among other things, lift trucks during loading or unloading.
Shelf-type storage racks are well known in the storage and warehouse industries. Such racks typically include at least four columns, two in the front or access aisle and two in the back. Lateral beams interconnect the pairs of front columns and pairs of back columns. The lateral beams, in conjunction with optional cross members between the lateral beams, form shelves used for storage of pallets and their loads. Typically, there is a shelf approximately 48 inches from the ground and then shelves above the lowest shelf spaced approximately every 48 inches, or for other loads at load required increments.
Each pair of front and back columns are provided with transverse support beams that interconnect the front and back columns. Diagonal support braces between the front and back columns may also be provided for increased strength, rigidity and stiffness. Each pair of front and back columns and the associated beams and braces are typically referred to in the industry as rack trusses. Each pair of opposing rack trusses, and their interconnecting lateral beams, form a typical shelf-type storage rack. The racks may be placed side-by-side and/or back-to-back in arrays to form the desired storage rack system.
The components that form the storage rack trusses, such as the transverse supports and diagonal support braces, are typically welded together and painted at the fabrication site and then shipped to the storage facility where they are installed for use. For example, the transverse supports and any diagonals are typically welded to the front and back columns to form the rack truss. Once at the storage facility, the lateral beams interconnecting each opposing pair of trusses are installed by welding or bolting (see e.g., U.S. Pat. No. 4,678,091). The bottom of the columns of the rack trusses may be placed directly on the warehouse floor. Because the trusses are fabricated prior to shipping and installation, known rack trusses are somewhat difficult to handle during assembly, take-up more space during shipping and can be difficult to paint. In addition, because the rack trusses are welded prior to shipment and assembly, the truss components cannot be easily replaced if damaged after installation.
In use, the pallets and their loads are placed on or removed from the shelves using a fork lift truck. Experience has shown that the bottom portion of the rack truss and particularly, the bottom 4-6 inches of the truss, take the most abuse. For example, the bottom portion of the front columns at the access aisle, are often bumped by pallets or the forks of a lift truck during the placement or removal of pallets and their loads. This can result in, among other things, a weakened rack structure.